How to align multiple wave textures?
A very flexible way to make the texture is to make it from scratch with the nodes, not relying on the built-in, a bit limited wave texture. Using some math nodes and adjusting the value results in a pretty nice wood texture.





Here the two vector inputs define a line that passes through both (the core of the three), and the distance from that to the object surface is calculated inside the distance node. 



The surface positions are distorted a bit by adding a bit of noise to them, the distance calculation is done per the equation here.

Using modulo makes the distance from the surface to the line a looping range of values from 0 to the distance between the waves in the wood. Multiplying that by the inverse of the distance brings the range to 0 - 1, which can then be mapped into a nice gradient using a map range node. That can be used to multiply or mix the color value to achieve the final result.

See also:


http://www.minimaexpresion.es/?p=690&amp;lang=en
http://materialw.wordpress.com/materials/wood-material/
http://blenderartists.org/forum/showthread.php?246113-A-fine-procedural-wood-material-for-Cycles
http://shiny-dynamics.blogspot.fr/2012/04/wood-texture-for-blender.html
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Procedural_Textures
http://wiki.blender.org/index.php/Doc:2.6/Manual/Textures/Types/Procedural/Wood
http://www.blendswap.com/blends/view/52626 (mirror of previous link)